Handling webs of material

ABSTRACT

Relative displacement, at a working site, between first and second webs of material in face-to-face contact at that site is inhibited by selecting the first web to be of smaller surface area than the second at the site and by establishing thereat a reduced pressure adjacent that face of the first web which is away from the second web, thereby causing the second web to be drawn against the first web at the working site.

United States Patent 1 Watts et al.

[ HANDLING WEBS OF MATERIAL [75] Inventors: Peter Edward Watts, Earley; Alan Walter Kent, Frimley; Kenneth ORiley, Weybridge, all of England [73] Assignee: Vickers Limited, London, England [22] Filed: Feb. 5, 1973 [21] Appl. No.: 329,369

[52] US. Cl 226/7, 226/97, 226/113,

269/21 [51] Int. Cl B65h 25/06 [58] Field of Search 226/7, 97, 113;

[56] References Cited UNITED STATES PATENTS 3,161,120 12/1964 Timares et al. 226/97 X 3,667,845 6/1972 Leavitt et a1 226/97 X 3,631,796 1/1972 Hastings ..269/21 3,294,392 12/1966 Dunham ..269/21 Primary Examiner-Allen N. Knowles Attorney-Robert D. Yeager et a1.

[5 7] ABSTRACT Relative displacement, at a working site, between first and second webs of material in face-to-face contact at that site is inhibited by selecting the first web to be of smaller surface area than the second at the site and by establishing thereat a reduced pressure adjacent that face of the first web which is away from the second web, thereby causing the second web to be drawn against the first web at the working site.

11 Claims, 4 Drawing Figures PAIENTEDamea um 3.767.097

SHEET 2 [IF 2 HANDLING WEBS or MATERIAL The present invention relates to the handling of webs of material and can be applied to processes in which an extended web of material is fed continuously or intermittently to a given site at which successive lengths of the web are subjected in turn to an operation of some kind. In co-pending British Patent application No. 8469/72, for instance, there is disclosed a method of performing a succession of stencil-cutting operations on respective lengths of stencil sheet material drawn off in succession from a continuous roll thereof to a predetermined stencil-cutting site, each of the lengths being removed from the stencil-cutting site, after having been there subjected to such an operation, to leave the site free for the next length. Thus a stencil-cutting operation is being carried out in turn on successive lengths of what is effectively a stencil sheet web. The stenci1- cutting operationmay be an internal stencil-cutting process in which a length of the stencil sheet web is arranged in substantially cylindrically-curved manner and an electrical stencil-cutting stylus is rotated, about the axis of curvature of the cylindrically-curved length of the web, so as to cut into the inwardly-looking face of this length of the stencil sheet web. Successive lengths of a stencil sheet web can be held in the required cylindrically-curved disposition for internal stencil-cutting by being held against the internal surface of an unclosed cylindrically-curved support, hereinafter referred to as a cutting cylinder. To hold such a length of the web against the internal surface of the cutting cylinder, the cylinder can be provided with perforations arranged so that the establishment of a region of reduced fiuid pressure externally of the cutting cylinder causes the length of web to be sucked against the internal surface of the cylinder so as to assume the cylindrical shape thereof. Usually, when a stencil sheet is cut a backing sheet is provided adjacent thereto, the combination of stencil sheet and backing sheet being known as a stencil blank. Accordingly, respective lengths of stencil sheet material and backing sheet material can be simultaneously drawn off from separate reels or rolls of stencil sheet material and backing sheet material, respectively, and drawn together into the interior of the cutting cylinder of an internal stencilcutting apparatus, so that within the apparatus the stencil sheet web and the backing sheet web combine to form a length of stencil blank. Whereas a'single web can be successfully fed around the internal surface of the cutting cylinder, the presence of an additional adjacent web gives rise to problems associated with relative' movement between the two webs; for example, puckering and creasing of the webs may occur. While the lower web will be sucked against the internal surface of the cutting cylinder, the same will not be true of the upper web.

Combined webs are employed in various office and industrial printing machines and other web-handling machines. Continuous stationery machines, for example, may deal with combined webs consisting of two or more component webs capable of displacement relative to one another. Combined webs may of course comprise adjacent webs of different thickness which may or may not be of the same material. Typically, the web material may be paper, foil, or plastics strip or tissue, or a combination of such materials.

jacent webs in a combination of webs can be crimped together along one or both of their edges at the location where the component webs first meet in the relevant machine. In this case, however, it may be necessary to separate the crimped webs as a final operation at the output end of the machine, and accordingly provide means for the purpose.

It is an object of the invention to provide a method and an apparatus whereby the relative positioning, at a working site, of two webs of material in face-to-face contact at that site can be controlled in a manner over coming the disadvantages discussed above.

According to one aspect of the invention, there is provided a method of inhibiting relative movement between first and second webs of material that are fed to a working site at which the webs lie face to face, wherein the said first web is selected to be of smaller surface area than the second web at the working site; and a reduced pressure is established, at that site, adja cent that face of the first web which is away from the second web; said reduced pressure acting on the second web, to draw the second web against the first web, by virtue of said smaller surface area.

According to another aspect of the invention, there is provided an apparatus for controlling the positioning of first and second webs, compirising:

web support means defining a working site at which respective lengths of the first and second webs are provided face to face, the first web being of smaller surface area than the second at said working site; and pump means, in communication with said working site, for establishing a reduced pressure adjacent that face of the first web which is away from the second web at the working site, said reduced ppressure acting on the second web, to draw the second web against the first web, by virtue of said smaller surface area.

The web support means of apparatus embodying the I invention may for example comprise a support member bounding the working site so as to provide thereat a support surface for the first web, this member being provided with apertures which open into its support surface and are in communication with the pump means of the apparatus.

So that the surface area of the first web at the working site is smaller than the surface area of the second web at that site, the first web may be provided with apertures through which the reduced pressure established adjacent to the outer face of the first web at the working site can act on the second web so as to draw it against the first web. Where apparatus embodying the invention has web support means comprising an apertured support member such as mentioned above, the first web should be arranged so that the apertures therein are not in register with those of the support member.

Alternatively or additionally, the first web may be made narrower than the second web so that the reduced pressure can act upon lateral edge regions of the second web that extend beyond respectively adjacent lateral edges of the first web at the working site. This action may be enhanced by the provision of web support means including wall means extending along and around mutually adjacent lateral edge regions of the respective webs at the working site, so that there is defined between the wall means and the mutually adjacent lateral edge regions of the respective webs at least one passageway whereby air or other fluid in a region adjacent to that face of the second web which is away from the first web can communicate with the region of reduced pressure established adjacent to that face of the first web which is away from the second web at the working site. Such wall means can additionally serve to guide the longitudinal motion of the webs at the working site when passing to or from the site.

An apparatus embodying the invention may include web supply means for delivering respective lengths of the first and second webs of material in succession to the working site, either continuously or intermittently.

Where sufficient pressure is maintained between the adjacent webs in a method or apparatus embodying the invention, the two webs will register satisfactorily and exhibit a good resistance to displacement relative to one another but, at the same time, when the combined webs are fed to a location where there is no difference in pressure on the respective outer sides of the webs, the adjacent webs can be easily separated from one another for passing on to different respective locations.

It will be appreciated that the invention can be applied to a combination of more than two adjacent webs.

Reference will now be made, by way of example, to the accompanying diagrammatic drawings, in which:

FIG. 1 is a schematic radial sectional view of part of an internal stencil-cutting apparatus embodying the invention for carrying out a method embodying the invention,

FIGS. 2a and 2b are respective schematic fragmented axial cross-sectional views of part of the apparatus when set up with two different forms of backing sheet, and

FIG. 3 is a perspective view of part of the apparatus slightly modified.

In FIG. 1 there are shown a reel or roll 1 of stencil sheet material 1 and a reel or roll 22 of backing sheet material 2'. The reels 1 and 2 are mounted rotatably with their axes parallel so that successive lengths of stencil sheet material 1 and backing sheet 2' can be respectively drawn off the reels 1 and 2 as a stencil sheet web 3 and a backing sheet web 4 onto a common feedin roller 5. The feed-in roller 5 extends along one side of an axially-extending gap 6 in a cutting cylinder 7 defining a stencil-cutting site. The cutting cylinder 7 has radially extending holes 8 drilled therethrough, these holes being circumferentially distributed around the cylinder adjacent to its axial edge regions. At the top of the roller 5 the stencil sheet web 3 from the reel 1 comes into contact with the backing sheet web 4 from the reel 2 and thereafter the two webs pass through the apparatus face to face. The webs 3 and 4 pass adjacent to one another into the interior of the cutting cylinder 7 so as to follow the internal circumference of the cylinder 7 until the adjacent webs emerge from the cylinder between two web drive rollers 9 and 10 extending along the other side of the axially-extending gap 6 in the cylinder 7.

To hold the lengths of the backing sheet web 2 in the cylinder 7 in a cylindrical disposition, pump means comprising a vacuum blower 11 arranged externally of the cylinder 7 are employed to create a region of low pressure around the outside of the cylinder. Consequently, air is sucked through the holes 8 from the space defined between the internal surface of the cylinder 7 and the outer surface of that length of the backing sheet web 4 which is within the cylinder. This length of the backing sheet web 4 is accordingly sucked against the internal surface of the cylinder 7 and so assumes the cylindrical shape thereof. The whole of the backing sheet web 4 from the reel 2 can be provided with respective sets of perforations 14 (not seen in FIG. 1) along both edge regions thereof, thus making the surface area of this web smaller than that of the stencil sheet web 3. In this case, these perforations are positioned such that they do not register with the holes 8 in the cylinder 7 when any given length of the backing sheet web 4 is within the cylinder. Thus when the vacuum blower 1 1 is operating, air in the space defined between the adjacent lengths of the stencil sheet web 3 and the backing sheet web 4 within the cylinder 7 is sucked out through the holes in the backing sheet web 4 into the space defined between the internal surface of the cylinder 7 and the backing sheet web 4. Hence, the length of the stencil sheet web 3 within the cylinder 7 is sucked against the adjacent length of the backing sheet web 4 as the latter is sucked against the internal surface of the cylinder 7. The degree of vacuum achieved with the vacuum blower 11 is sufficient for the adjacent lengths of the webs 3 and 4 to remain constrained into the cylindrical shape of the internal surface of the cutting cylinder 7 as the web drive rollers 9 and 10 are operated to draw the adjacent webs 3 and 4 out of the cylinder 7. Thus as one length of the web 3 and an adjacent length of the web 4 are extracted from the interior of the cutting cylinder 7, a succeeding length of the web 3 and a corresponding length of the web 4 are drawn together over the roller 5 into the interior of the cylinder 7 so as to occupy the respective dispositions previously occupied by the adjacent extracted lengths of the webs 3 and 4. The small arrows seen in FIG. 1 illustrate the direction of air flow, the larger arrows indicating the direction of web movement.

With adjacent lengths of the webs 3 and 4 held against one another in cylindrically curved disposition within the cylinder 7, a stencil cutting operation can be performed. For this purpose, an electrical stencilcutting stylus (not shown) mounted with the cylinder 7 so as to rotate about the axis thereof is made to traverse axially of the cylinder as it rotates therewithin adjacent to the inner surface of the length of the stencil sheet web 3 within the cylinder. The degree of cutting effected by the stylus, at any point on this length of the stencil sheet web, through the stencil sheet web is controlled in accordance with the degree of blackness" of the corresponding point of an original the image of which is to be reproduced in the stencil sheet web. The greater the blackness" at a point of the original, the greater the quantity of material removed from the stencil sheet web 3 at the corresponding point thereof.

After a stencil-cutting operation, the adjacent lengths of the webs 3 and 4 can be drawn out between the rollers 9 and 10. Once past the rollers 9 and 10, the two webs 3 and 4 can be separated from one another since they are no longer held together under the action of differential pressure. As an alternative to passing the respective lengths of the webs 3 and 4 together between the rollers 9 and 10, the backing sheet web 4 may be arranged to pass alone between the rollers 9 and 10 while the stencil sheet web is diverted along a path extending over and above the rollers 9 and I0, separtion of the two webs in this case taking place before entry of the backing sheet web between the rollers 9 and 10. Once separated from the previously adjacent length of backing sheet web 4, a length of cut stencil sheet web 3 can, for example, be directly fed onto a duplicator drum and then severed from the rest of the stencil sheet web 3 if it has not already been so, while the corresponding length of the backing sheet web 4 may be fed into a disposal bin.

So that the two webs 3 and 4 are held together with sufficient pressure, the stencil sheet web 3 and the backing sheet web 4 must initially be in sufficient proximity to one another to allow the establishment of a suitable degree of vacuum between them. For this purpose, as seen in FIG. 2a, two guides 12 are respectively provided at the opposed axial edges of the cutting cylinder 7. The guides 12 are in the form of circumferentially extending end caps adapted to restrict movement of the stencil sheet web 3 and the backing sheet web 4 radially away from the internal surface of the cutting cylinder 7 as well as axially over that surface and to define respective air-flow passageways around the pairs of mutually adjacent lateral edge regions of the webs 3 and 4. Typically, the thickness of the backing sheet web will be of the order of 0.0035 inches and the thickness of the stencil sheetweb of the order of 0.0023 inches, in which case the radial gaps 13 between the guides and the respective radially opposed inner surface portions of the cutting cylinder 7 can appropriately be of the order of 0.015 inches. The exact size of these gaps is not critical, but the adjacent lengths of the stencil sheet web 3 and the backing sheet web 4 should always be sufficiently close to one another to allow a sufficient degree of vacuum to be established between them. The guides 12 extend axially over the edge regions of the combined webs 3 and 4 for about half an inch at each edge; again, however,.this is not a critical dimension. The holes 8 provided in the cutting cylinder 7 and the perforations l4, staggered relatively to the holes 8, provided in the backing sheet web 4 are arranged so as to lie outside the area traversed by the electrical stencilcutting stylus during a cutting operation since, otherwise, these holes and perforations might show up in the eventual stencilcopy. A sufficient vacuum pressure to obtain adequate location of the webs 3 and 4 is in the region of 1.5 to 3.5 cm of mercury; to achieve this, it is sufficient for the vacuum blower 11 to be a conventional centrifugal exhauster.

Instead of providing the backing sheet web 4 with perforations 14 as illustrated in FIG. 2a to ensure that the surface area of this web is smaller than that of the stencil sheet web 3, the backing sheet web 4 may be narrower than the stencil sheet web, as illustrated in FIG. 2b which, in other respects, resembles FIG. 2a. With the backing sheet web 4 narrower than the stencil sheet web 3 the lateral borders of the stencil sheet web are subjected to the suction effect sufficiently for the v stencil sheet web to be held against the backing sheet web as the latter is itself held under suction against the internal surface of the cutting cylinder 7.

It will be appreciated that the guides 12 are not strictly necessary in either of the cases illustrated in FIGS. 2a and 2b to achieve the desired retention of both webs in the cutting cylinder 7 under the suction effect produced by the blower 11. The presence of these guides 112, however, enhances this effect and, also, in addition to preventing lateral displacement of the webs 3 and 4 in the cutting cylinder 7, inhibits pulling of the webs 3 and 4 away from the internal surface of the cutting cylinder 7 when fresh lengths of the webs are being drawn into the cylinder.

The arrows in FIGS. 2a and 2b indicate the direction of air flow during operation of the blower 11.

In FIG. 3, parts already described are respectively denoted by the same reference numerals. For convenience, the reel 2 has been omitted. To assist in the meeting of the stencil sheet web 3 with the backing sheet web 4i at the roller 5, an additional roller 5 is provided adjacent to the roller 5 and parallel thereto, both of the component webs being fed in between the two rollers 5 and 5'. The arrows shown in FIG. 3 indicate the direction of movement of the parts concerned.

In applying the present invention to a combination of more than two adjacent webs, suitably positioned perforations may be provided along all but that web which is most remote from the region of reduced pressure, these perforations preferably being located along the outer edge regions of the webs concerned. The perforations in each perforated web should be staggered relative to the perforations in the or each adjacent perforated web in such a way as to ensure that air is sucked from between each adjacent pair of webs. Alternatively, where a combination of more than two adjacent webs is involved that web which is closest to the region of reduced pressure can be narrower than the adjacent web, which in turn should then be narrower than the next web, and so on. It is of course, necessary for the various component webs to be sufficiently dense and non-porous tr allow an adequate degree of vacuum pressure to be maintained to prevent slipping between the layers.

Although the drawings illustrate a case in which the component webs originate from separate sources and are drawn adjacent to one another at a location removed from those sources, it will be appreciated that the invention is equally applicable in cases where the webs originate from a common source. For example, the component webs may be respective adjacent but separable layers of a composite layered material wound on a reel or in a roll or extending as a belt, these layers remaining adjacent to one another throughout the handling of the webs or perhaps being separated from one another at some locations and being brought together again at others.

In a modified form of the illustrated apparatus, the roll 2 of backing sheet material 2' maybe replaced by a closed loop of backing sheet material 2' arranged so that it can be continuously recirculated through the apparatus adjacent to successive lengths of the stencil sheet web 3.

In addition to its applications to stencil-cutting the present invention may, for example, also be applied in the manufacture of interleaved stationery and of conventional stencil blanks as well as in the field of automatic photographic printing and in packaging processes involving the use of multi-layer wrapping materials.

What is claimed is:

1. A method of inhibiting relative movement between first and second webs of material that are fed to a working site at which the webs lie face to face, wherein the said first web is selected to be of smaller surface area than the second web at the working site; and a reduced pressure is established, at that site, adjacent that face of the first web which is away from the second web; said reduced pressure acting on the second web, to draw the second web against the first web, by virtue of said smaller surface area.

2. The method of claim 1, wherein the first web is provided with apertures to make it of smaller surface area than the second web at the working site.

3. The method of claim 2, wherein said apertures are confined to lateral edge regions of the first web.

4. The method of claim 1, wherein lateral edge regions of the second web extend beyond respectively adjacent lateral edges of the first web at the working site.

5. The method of claim 1, wherein said working site is bounded by wall means extending along and around mutually adjacent lateral edge regions of the respective webs, there being defined between said wall means and said mutually adjacent lateral edge regions at least one passageway whereby a region adjacent that face of the second web which is away from the first web communicates with the region of reduced pressure adjacent that face of the first web which is away from the second web.

6. The method of claim 5, wherein said wall means are arranged to guide longitudinal motion of the webs at the working site.

7. Web-handling apparatus for controlling the positioning of first and second webs, comprising:

web support means defining a working site at which respective lengths of the first and second webs are provided face to face, the first web being of smaller surface area than the second at said working site;

and pump means, in communication with said working site, for establishing a reduced pressure adjacent that face of the first web which is away from the second web at the working site, said reduced pressure acting on the second web, to draw the second web against the first web, by virtue of said smaller surface area.

8. The apparatus of claim 7, including wall means arranged to extend along and around mutually adjacent lateral edge regions of the respective webs such that there is defined between said wall means and said mutually adjacent lateral edge portions at least one passageway whereby a region adjacent that face of the second web which is away from the first web communicates with the region of reduced pressure adjacent that face of the first web which is away from the second web.

9. The apparatus of claim 8, wherein said wall means are arranged to guide longitudinal motion of the webs at the working site.

10. The apparatus of claim 7, wherein the web support means comprise a support member providing a support surface for the first web at the working site, said support member being provided with apertures which open into said support surface and are in communication with said pump means.

11. The apparatus of claim 7, including web supply means for delivering the respective lengths of the first and second webs to the working site.

- UNITED STATES PATENT OFFICE CERTIFICATE OF C@RECTE@N Patent No. 3,767,097 Dated October 23, 1973 inventor) Peter Edward Watts, Alan Walter Kent Kenneth,- O'Riley It is certi'fied'that error appears in the above-idefitifie'dpatent and that said Letters Patent are herebycorrected as shown below:

On the Title Pagefcol. .1, after "[21] A ly N0 329,369", the following should beinserted; I

v [30] ii Foreign Application Priority Data February 23; 1972 Great Britain 8470/72.

FORM PC4050 i USCO MM-DC scan-P69 u.s. sovznnnzmmm'me OFFICE 1959 o-aea-au. 3Q

o UNITED STATES PATENT oFFicE @ERTIFICATE OF COREC'HON Patent No. ,7 7, 97 Dated October 23, 1973 I t r( Peter Edward Watts, Alan Walter Kent, Kenneth O'Riley a e 2 It is certified that error appears in the abo re identi'fied patent and that said-Letters Patent are hereby corrected as shown below:

Column 2, line 44, "ppressur e" should read --pressu re-;

Column 3, line 46, "22" should read -2-;

Column 6 ,'f'line 39, "tr" should read --to.

Signed and sealed this 19th day of February 1974.

(SEAL) Attest: EDWARD M.FL TGHER",JRL I c. MARSHALL DANN Attesting Officer Commissioner of Patents FORM PO-105O (10-69) USCOMM-DC 60376-P69 is U. 5. GOVERNMENT PRINTING OFFICE I909 0-368-33L 

1. A method of inhibiting relative movement between first and second webs of material that are fed to a working site at which the webs lie face to face, wherein the said first web is selected to be of smaller surface area than the second web at the working site; and a reduced pressure is established, at that site, adjacent that face of the first web which is away from the second web; said reduced pressure acting on the second web, to draw the second web against the first web, by virtue of said smaller surface area.
 2. The method of claim 1, wherein the first web is provided with apertures to make it of smaller surface area than the second web at the working site.
 3. The method of claim 2, wherein said apertures are confined to lateral edge regions of the first web.
 4. The method of claim 1, wherein lateral edge regions of the second web extend beyond respectively adjacent lateral edges of the first web at the working site.
 5. The method of claim 1, wherein said working site is bounded by wall means extending along and around mutually adjacent lateral edge regions of the respective webs, there being defined between said wall means and said mutually adjacent lateral edge regions at least one passageway whereby a region adjacent that face of the second web which is away from the first web communicates with the region of reduced pressure adjacent that face of the first web which is away from the second web.
 6. The method of claim 5, wherein said wall means are arranged to guide longitudinal motion of the webs at the working site.
 7. Web-handling apparatus for controlling the positioning of first and second webs, comprising: web support means defining a working site at which respective lengths of the first and second webs are provided face to face, the first web being of smaller surface area than the second at said working site; and pump means, in communication with said working siTe, for establishing a reduced pressure adjacent that face of the first web which is away from the second web at the working site, said reduced pressure acting on the second web, to draw the second web against the first web, by virtue of said smaller surface area.
 8. The apparatus of claim 7, including wall means arranged to extend along and around mutually adjacent lateral edge regions of the respective webs such that there is defined between said wall means and said mutually adjacent lateral edge portions at least one passageway whereby a region adjacent that face of the second web which is away from the first web communicates with the region of reduced pressure adjacent that face of the first web which is away from the second web.
 9. The apparatus of claim 8, wherein said wall means are arranged to guide longitudinal motion of the webs at the working site.
 10. The apparatus of claim 7, wherein the web support means comprise a support member providing a support surface for the first web at the working site, said support member being provided with apertures which open into said support surface and are in communication with said pump means.
 11. The apparatus of claim 7, including web supply means for delivering the respective lengths of the first and second webs to the working site. 